I’m working on a Epiphone Valve Senior guitar amp that works fine I will try to attach a schematic with some voltages I measured added, but. Looking at the schematic I think you could borrow two 12AX7s from the Valve Sr to use as a preamp tube in the Valve Junior Reverb unit but. Download GIBSON EPIPHONE VALVE JR service manual & repair info for electronics experts.

Author: Tojagami Balabar
Country: Pakistan
Language: English (Spanish)
Genre: Politics
Published (Last): 23 August 2012
Pages: 455
PDF File Size: 7.94 Mb
ePub File Size: 12.82 Mb
ISBN: 471-8-76218-441-1
Downloads: 96870
Price: Free* [*Free Regsitration Required]
Uploader: Kazralkree

I found this photo from summer namm last year: If anyone has a scgematic opinion, please do not be a “hater” as the kids like to say on the World Wide Webbut offer an alternative suggestion.

Then checked the heater voltages on each tube, also stayed constant when the output dropped. What is that supposed to do? Help Senlor Go to top. Posted 14 December – Maybe epiphone will reveal more news at the upcomming Winter Namm No, create an account now. If you don’t like the sound of the reverb in your Valve Senior I wouldn’t reuse any of the parts to make a Valve Jr into a reverb unit. What do you suggest to try next?

Epiphone Valve SENIOR | Harmony Central

I’ll also give him your list and ask for his opinion as well no offense intended. Originally Posted by Urinate Forever And wiklund is smart, i’m seniot agreement with him.

You can find a schematic of the amp here: Anyone know anything about it? Does the problem still occurs? Now I have to decide between this and the others Can you repost the schematic?

Gibson Brands Forums: Valve senior Mods. – Gibson Brands Forums

Heater voltage pin 2 or 7 referenced to ground starts at 3 VAC until standby switch is turned off, then stays steady at 2. I’ll just add, because maybe you don’t seem convinced, that internal oscillation is the first suspect and we haven’t eliminated that possibility yet. Music-diverApr 2, Lately I have gone more in the acoustic direction so I haven’t really looked around for amps in a few months.


If you are comfortable working with the amp on, and can avoid the various high voltage sources, my next step would be leaving the preamp valves out and producing the fault condition, then moving leads around to see if it changes and trying to stop it that way.

As far as oscillation, I looked for any trace of such on the speaker output with the scope starting at the lowest output and raising gain until output dropped. We’re trying to work out which section of the amp has the problem. Delete From Topic The post will be removed from this topic completely.

Supporting Member Alex R’s Avatar Join Date: DC voltage remains steady on both plate and screen grids at and respectively with light bulb current limiter in line of the supply AC Heater voltage pin 2 or 7 referenced to ground starts at 3 VAC until standby switch is turned off, then stays steady at 2. As for your warnings, I know two things about amps. This may be an oscillation at some stage and past this stage you get only distored signal.

V1 has been removed for some time, 2 weeks? It is serving no purpose. Is that where you meant? Some people like to use as high as uf for the power amp C With V1 and V2 removed, signal injected to C13, I have rerouted the output leads and tried holding them as far away from the power tubes as I could with no change. Yes, it looks like you are conducting every possible test but not the basic one we suggested: Since you cannot see it, I would suggest detecting at which stage the signal dissapears.


Login or Sign Up. I presume you meant C24?

You see if Enzo says something the rest of us just nod in sage silence, but really it’s what we’re all thinking Alas we still have some confusion about tube numbering.

So I haven’t seen any responses on this post for a couple days now, am I doing something, or not doing something correctly? The problem is that the tube is running too hot for the reverb tank.

Posted 15 November – T here is not really one single mod that will bring the amp to life, but a combination of upgrades and “tweaks”. I have found that the Mullard and Tung Sol reissues sound far superior to any other tubes.

So try injecting a signal with V1 and V2 unplugged, if that’s not what you’ve already done. Yes the attenuation drop off problem still occurs in that case Installed V2 and put the signal back to the input jack, virtually no output, installed V3 and problem still occurs.

My opinions are based on my personal experience. Can I use parts of the valve senior to do this mod? It is oscillating at frequencies above audio. You should keep a copy of this. Results 1 to 35 of Quick fix would be best. I think my next suspect would be a bad OT but that’s a long way second to oscillation.

I have a second “updated” schematic from Gibson but it has no call outs, r3, c5, etc. This will smooth the AC hum, valge keep your amp whisper quiet, even when “dimed”.

I have a “recipe” that I’ve been dying to share. Unless you meant to leave V3 in place I can’t schejatic a signal out with input signal attached to C13 because V3 is removed.